1. Field of the Invention
The present invention relates to a semiconductor device having a semiconductor sensor chip.
2. Description of Related Art
Acceleration and angular velocity sensors (gyroscope) are typically known as semiconductor sensor chips for detecting motions by changes of stress and displacement of a movable portion. It is also known that such semiconductor sensor chips are fabricated through three-dimensional processing implemented on silicon by using a silicon micro-machining technology for example.
Normally, the semiconductor device is constructed by mounting the semiconductor sensor chip within a hollow case so that its sensor section (operating section) is not affected (see Japanese Patent Application Laid-Open Nos. 2003-163304, 9-292408 and 2005-127750, for example).
As typified by the patent documents cited above, the case for mounting the semiconductor sensor chip is constructed as follows for example:
1) construct by members made from ceramics; and
2) a semiconductor chip for processing output signals of the semiconductor sensor chip, i.e., a silicon substrate, is mounted as a part of the case and is combined with a glass member.
However, there have been problems that the case composed of the member made from ceramic is very expensive and that the case constructed by coupling members of different types of materials such as the combination of silicon and glass member is easy to be broken from a difference of their coefficient of expansion.